Selective Response of Dermal Th‐1 Cells to 20–50 kDa Streptococcal Cell‐Wall Proteins in Chronic Plaque Psoriasis

• Published in: Scandinavian journal of immunology 2003-09, Vol.58 (3), p.335-341
• Main Authors: Baker, B. S., Ovigne, J.‐M., Fischetti, V. A., Powles, A., Fry, L.
• Format: Article
• Language: English
• Subjects: Adult; Aged; Antigen Presentation - immunology; Antigens, Bacterial - immunology; Antigens, Bacterial - pharmacology; Bacterial Outer Membrane Proteins - immunology; Bacterial Outer Membrane Proteins - pharmacology; Cell Line; Cell Wall - immunology; Cell Wall - microbiology; Electrophoresis, Polyacrylamide Gel; Epitopes; Female; Flow Cytometry; HLA-DR Antigens - immunology; Humans; Male; Middle Aged; Psoriasis - immunology; Psoriasis - microbiology; Skin - cytology; Skin - immunology; Skin - microbiology; Streptococcal Infections - immunology; Streptococcus - immunology; Th1 Cells - immunology; Th1 Cells - microbiology
• ISSN: 0300-9475; 1365-3083
• DOI: 10.1046/j.1365-3083.2003.01309.x

We have recently described a dermal Th‐1 subset in skin lesions of psoriasis which recognizes cell‐wall extract isolated from group A streptococci (GAS). As a first step in the identification of the streptococcal proteins involved, dermal T‐cell lines (TCL) cultured from the lesional skin of 12 human leucocyte antigen (HLA)‐typed psoriasis patients were stimulated with GAS cell‐wall extract and 14 fractions (MWt approximately 20–100 kDa) separated from the cell‐wall extract by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) and electroelution, stained for intracellular interferon‐γ(IFN‐γ) expression and analysed by flow cytometry. All the TCL responded to GAS cell‐wall extract to varying extents (3.5–27.6% IFN‐γ+). This response was consistently directed against 20–50 kDa cell‐wall fractions and inhibited by anti‐HLA‐DR antibody. TCL with higher responses to GAS cell‐wall extract recognized a larger number of fractions within this range than the lower responder TCL. No difference between the level and pattern of response to the fractions was observed for TCL from HLA‐DR7+ (n = 6) and HLA‐DR7– (n = 6) individuals. This preliminary study has shown a selective response to lower MWt proteins expressed on GAS cell wall by skin Th‐1 cells in psoriasis. Further studies are required to identify the proteins involved.